4.1.2.1 Logging hooks

Most diagnostic messages displayed by radiusd describe
some events that occured while processig a certain incoming request.
By default they contain only a short summary of the event.
Logging hooks are means of controlling actual amount of
information displayed in such messages. They allow you to add to the
message being displayed any relevant information from the incoming
request that caused the message to appear.

A hook is a special Rewrite function that takes three arguments
and returns a string. There are two kinds of logging hooks: prefix
and suffix. Return value from the prefix hook function will
be displayed before the actual log message, that of the suffix hook
function will be displayed after the message.

Furthermore, there may be global and channel-specific
hooks. Global hooks apply to all categories, unless overridden by
category-specific hooks. Global prefix hook is enabled by
prefix-hook statement appearing in the logging block.
Global suffix hook is enabled by suffix-hook statement.
Both statements take as their argument the name of corresponding
Rewrite function.